U.S. patent number 5,395,434 [Application Number 08/087,069] was granted by the patent office on 1995-03-07 for ink, ink-jet recording method, and ink-jet recording apparatus.
This patent grant is currently assigned to Canon Kabushiki Kaisha. Invention is credited to Fumihiro Gotoh, Shinichi Sato, Hitoshi Sugimoto, Shinichi Tochihara, Masaya Uetuki.
United States Patent |
5,395,434 |
Tochihara , et al. |
March 7, 1995 |
**Please see images for:
( Certificate of Correction ) ** |
Ink, ink-jet recording method, and ink-jet recording apparatus
Abstract
Provided is an ink for ink-jet recording, comprising a dye,
water, and the components (a), (b), and (c) below: (a) at least one
surfactant selected from the group consisting of higher
alcohol-ethylene oxide adducts represented by General Formula [1],
alkylphenol-ethylene oxide adducts represented by General Formula
[2], ethylene oxide-propylene oxide copolymers represented by
General Formula [3], and acetylene glycol-ethylene oxide adducts
represented by General Formula [4], at a content of from 0.1 to 20%
by weight; where R is alkyl, and n is an integer; ##STR1## where R
is alkyl, and n is an integer; ##STR2## where R is alkyl or
hydrogen, and n and l are respectively an integer; ##STR3## where m
and n are respectively an integer; (b) thiodiglycol; and (c) urea
or a derivative thereof.
Inventors: |
Tochihara; Shinichi (Hadano,
JP), Sugimoto; Hitoshi (Kawasaki, JP),
Sato; Shinichi (Yokohama, JP), Gotoh; Fumihiro
(Yokohama, JP), Uetuki; Masaya (Kawasaki,
JP) |
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
|
Family
ID: |
27303512 |
Appl.
No.: |
08/087,069 |
Filed: |
July 7, 1993 |
Foreign Application Priority Data
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Jul 10, 1992 [JP] |
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4-183992 |
Jul 10, 1992 [JP] |
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4-183993 |
Mar 17, 1993 [JP] |
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5-081164 |
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Current U.S.
Class: |
106/31.43;
106/31.58; 106/31.59; 347/100 |
Current CPC
Class: |
C09D
11/38 (20130101) |
Current International
Class: |
C09D
11/00 (20060101); C09D 011/02 () |
Field of
Search: |
;106/22R,22H,2D
;346/1.1,46 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
0272936 |
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Jun 1988 |
|
EP |
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0404494 |
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Dec 1990 |
|
EP |
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0447896 |
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Sep 1991 |
|
EP |
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0483610 |
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May 1992 |
|
EP |
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55-29546 |
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Mar 1980 |
|
JP |
|
56-5871 |
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Jan 1981 |
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JP |
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56-57862 |
|
May 1981 |
|
JP |
|
2199041 |
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Jun 1988 |
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GB |
|
Other References
Derwent Abstract (WPI) No. 84-103558 with respect to Japanese
Patent Document No. 59-045372 (Sep. 7, 1982). .
Derwent Abstract (WPI) No. 82-98521E with respect to Japanese
Patent Document No. 57-164169 (Apr. 3, 1981). .
Derwent Abstract (WPI) No. 82-10725E with respect to Japanese
Patent Document No. 56-167775 (May 29, 1980)..
|
Primary Examiner: Klemanski; Helene
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper &
Scinto
Claims
What is claimed is:
1. An ink for ink-jet recording, comprising a dye, water and the
components (a), (b), and (c):
(a) at least one surfactant selected from the group consisting of
higher alcohol-ethylene oxide adducts represented by general
Formula (1), alkylphenol-ethylene oxide adducts represented by
general Formula (2), ethylene oxide-propylene oxide copolymers
represented by general Formula (3), and acetylene glycol-ethylene
oxide adducts represented by general Formula (4), at a content of
from 0.1 to 20% by weight;
where R is alkyl, and n is an integer; ##STR18## where R is alkyl,
and n is an integer; ##STR19## where R is alkyl or hydrogen, and n
and l are respectively an integer; ##STR20## where m and n are
respectively an integer; (b) thiodiglycol; and
(c) urea or a derivative thereof.
2. An ink for ink-jet recording according to claim 1, wherein the
ink contains thiodiglycol at a content of from 1 to 30% by
weight.
3. An ink for ink-jet recording according to claim 1, wherein the
ink contains urea or the derivative thereof at a content of from 1
to 30% by weight.
4. An ink for ink-jet recording according to claim 1, wherein the
value of n or n+m in general Formulas [1] to [4] is from 4 to
20.
5. An ink-jet recording method comprising the steps of:
(i) selecting an ink comprising a dye, water, and the components
(a), (b), and (c):
(a) at least one surfactant selected from the group consisting of
higher alcohol-ethylene oxide adducts represented by general
Formula (1), alkylphenol-ethylene oxide adducts represented by
general Formula (2), ethylene oxide-propylene oxide copolymers
represented by general Formula (3), and acetylene glycol-ethylene
oxide adducts represented by general Formula (4), at a content of
from 0.1 to 20% by weight;
where R is alkyl, and n is an integer; ##STR21## where R is alkyl,
and n is an integer; ##STR22## where R is alkyl or hydrogen, and n
and l are respectively an integer; ##STR23## where m and n are
respectively an integer; (b) thiodiglycol; and
(c) urea or a derivative thereof; and
(ii) conducting recording on a recording medium with ink droplets
of said ink.
6. An ink-jet recording method according to claim 5, wherein ink
droplets are ejected by action of thermal energy applied to the
ink.
7. A color ink-jet recording method comprising the step of
conducting recording by ejecting droplets of ink of two or more
colors onto adjacent or superposed positions on a recording medium,
said ink comprising a dye, water and the components (a), (b), and
(c):
(a) at least one surfactant selected from the group consisting of
higher alcohol-ethylene oxide adducts represented by general
Formula (1), alkylphenol-ethylene oxide adducts represented by
general Formula (2), ethylene oxide-propylene oxide copolymers
represented by general Formula (3), and acetylene glycol-ethylene
oxide adducts represented by general Formula (4), at a content of
from 0.1 to 20% by weight;
where R is alkyl, and n is an integer; ##STR24## where R is alkyl,
and n is an integer; ##STR25## where R is alkyl or hydrogen, and n
and l are respectively an integer; ##STR26## (b) thiodiglycol; and
(c) urea or a derivative thereof.
8. A color ink-jet recording method according to claim 7, wherein
ink droplets are ejected by action of thermal energy applied to the
ink.
9. An ink containing at least a dye, a water-soluble organic
solvent, and water, said ink further comprising a compound of the
formula ##STR27## where R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are
respectively hydrogen, an alkyl or alkenyl group of 1 to 4 carbon
atoms, or a substituted or unsubstituted phenyl group; and m+n is
ranging from 0 to 50; and l is a number of 2 or more.
10. An ink according to claim 9, wherein the ink contains the
compound represented by general Formula [5] at a content of from
0.001% to 20% by weight.
11. An ink according to claim 9, wherein the water-soluble organic
solvent is selected from the group consisting of polyhydric
alcohols, monohydric alcohols, and derivatives thereof.
12. An ink-jet recording method comprising the steps of:
(i) selecting an ink comprising a dye, a water-soluble organic
solvent, water, and a compound of the formula ##STR28## where
R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are respectively hydrogen,
an alkyl or alkenyl group of 1 to 4 carbon atoms, or a substituted
or unsubstituted phenyl group; and m+n is ranging from 0 to 50; and
l is a number of 2 or more; and
(ii) conducting recording on a recording medium with ink droplets
of said ink.
13. An ink-jet recording method according to claim 12, wherein ink
droplets are ejected by action of thermal energy applied to the
ink.
14. A color ink-jet recording method comprising the step of
conducting recording by ejecting droplets of ink of two or more
colors onto adjacent or superposed positions on a recording medium,
said ink comprising a dye, a water-soluble organic solvent, water,
and the compound of the formula ##STR29## where R.sub.1, R.sub.2,
R.sub.3, and R.sub.4 are respectively hydrogen, an alkyl or alkenyl
group of 1 to 4 carbon atoms, or a substituted or unsubstituted
phenyl group; and m+n is ranging from 0 to 50; and l is a number of
2 or more.
15. A color ink-jet recording method according to claim 14, wherein
ink droplets are ejected by action of thermal energy applied to the
ink.
16. An ink-jet recording method according to any of claims 5, 7,
12, and 14, wherein the recording medium has fiber exposed on the
surface thereof.
17. A recording unit having an ink container portion for holding
ink, and a head portion for ejecting the ink as ink droplets, said
ink is as defined in claim 1 or 9.
18. A recording unit according to claim 17, wherein the head
portion comprises a head which ejects ink droplets by action of
thermal energy applied to the ink.
19. An ink cartridge comprising an ink container portion for
holding ink, said ink is as defined in claim 1 or claim 9.
20. An ink cartridge according to claim 19, wherein the ink
container portion is in a bag-shape structure.
21. An ink cartridge according to claim 19, wherein the ink
container portion has a liquid-contacting face formed of
polyolefin.
22. An ink-jet recording apparatus comprising the recording unit of
claim 17, wherein the ink employed comprises a dye, water and the
components (a), (b), and (c):
(a) at least one surfactant selected from the group consisting of
higher alcohol-ethylene oxide adducts represented by general
Formula (1), alkylphenol-ethylene oxide adducts represented by
general Formula (2), ethylene oxide-propylene oxide copolymers
represented by general Formula (3), and acetylene glycol-ethylene
oxide adducts represented by general Formula (4), at a content of
from 0.1 to 20% by weight;
where R is alkyl, and n is an integer; ##STR30## where R is alkyl,
and n is an integer; ##STR31## where R is alkyl or hydrogen, and n
and l are respectively an integer; ##STR32## where m and n are
respectively an integer; (b) thiodiglycol; and
(c) urea or a derivative thereof.
23. An ink-jet recording apparatus according to claim 22, wherein
the recording unit comprises a carriage.
24. An ink-jet recording apparatus, comprising an ink cartridge of
claim 19 and a recording head.
25. An ink-Jet recording apparatus of claim 24, the apparatus
further comprises an ink supplying system for supplying ink from
the ink cartridge to the recording head.
26. A color ink-jet recording method in which droplets of two or
more color inks are ejected in accordance of pulse signals onto
adjacent or superposed positions on a recording medium, said ink
comprises a nonionic surfactant in an amount of from 1.0 to 20.0%
by weight, the ink ejected for one pulse is in an amount of from 10
to 70 pl, and the feathering rate (A) defined by Equation [I] is in
the range of from 2.5 to 3.5:
where B is a diameter (.mu.m) of a dot formed on plain paper, and C
is a diameter (.mu.m) of the ejected ink droplet.
27. A color ink-jet recording method according to claim 26, wherein
the nonionic surfactant is at least one selected from the group
consisting of polyoxyethylene alkyl ether, polyoxyethylene phenyl
ether, polyoxyethylene-polyoxypropylene glycol,
polyoxyethylene-polyoxypropylene alkyl ether, and acetylene
glycol-polyethylene oxide adducts.
28. A color ink-jet recording method according to claim 26, wherein
the recording medium has fiber exposed on the surface thereof.
29. An color ink-jet recording apparatus which conducts recording
by ejecting droplets of two or more color inks onto adjacent or
superposed positions on a recording medium, said apparatus
comprises a recording means for conducting recording mode, by use
of an ink containing a nonionic surfactant in an amount of from 1.0
to 20.0% by weight, by ejecting the ink for one pulse in an amount
of from 10 to 70 pl to form ink dots at the feathering rate (A)
defined by Equation [I] is in the range of from 2.5 to 3.5:
where B is a diameter (.mu.m) of a dot formed on plain paper, and C
is a diameter (.mu.m) of the ejected ink droplet.
30. An ink-jet recording apparatus comprising the recording unit of
claim 17, wherein the ink employed comprises at least a dye, a
water soluble organic solvent, and water, said ink further
comprising a compound of the formula. ##STR33## where R.sub.1,
R.sub.2, R.sub.3, and R.sub.4 are respectively hydrogen, an alkyl
or alkenyl group of 1 to 4 carbon atoms., or a substituted or
unsubstituted phenyl group; and m+n is ranging from 0 to 50; and l
is a number of 2 or more.
31. An ink-jet recording apparatus according to claim 30, wherein
the recording unit comprises a carriage.
Description
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to an ink which provides excellent
color recording on plain paper such as wood-free paper,
medium-quality paper, bond paper, and paper for copying. The
present invention also relates to an ink-jet recording method, and
an ink-jet recording apparatus employing the above ink.
2. Related Background Art
Personal computers including desk-top types, lap-top types, and
book types have come to employ a color display unit in recent
years. Software is also directing to color representation.
Consequently, printers are changing from monocolor types to color
types.
Among recording methods employed by such printers, ink-jet
recording is attracting attention. In ink-jet recording, ink
droplets are ejected and are attached to a recording medium, such
as paper sheets, converted paper sheets, plastic films, and cloths
without contact of a recording head to the recording medium. The
ink-jet recording method is advantageous in that noise is not
produced because of non-contact of the recording head with the
recording medium, and high speed printing and color recording is
practicable.
In the ink-Jet recording method, it is required that (1) ink does
not cause running of ink at the recorded portion on the recording
medium, (2) ink is sufficiently stable during storage, and (3) the
safety is high. In color ink-jet recording, it is further required
that (4) mixing(or bleeding) of different colors of inks caused by
unfixed ink droplets does not occur on contact of different color
inks on a recording medium, (5) a solid color portion is uniform in
color, and (6) failure of ink ejection does not occur after
interruption of ink ejection (first-ejection difficulty), since
limited colors of inks are more frequently used in color printing,
unlike monocolor printing.
However, conventional inks per se are not usable as inks for color
recording because they cause serious bleeding and do not give
high-quality images. Presumably, the bleeding is caused by the fact
that the ink is dotted before the previously dotted different color
of ink has been sufficiently fixed. Coated paper, which has high
ink-absorbing ability, is used for color recording in order to
prevent the bleeding. Further, for printing on plain paper such as
paper for copying and bond paper, a printing method reflecting upon
the fixing time of ink is proposed in which ink is dotted after the
previously dotted ink droplet has been fixed. In such a printing
method, the speed of the paper feed has to be slowed down
disadvantageously, thereby the printing time becomes longer
irrespectively of the ink-dotting method. Therefore, high speed
printing, which is characteristic of ink-jet recording, cannot be
practised with such a printing method.
To shorten the fixing time, Japanese Patent Application Laid-Open
No. 55-29546 discloses a method in which a surfactant is
incorporated into ink in a larger amount than usual and thereby the
ink seems to become dry instantaneously owing to the increased
penetration power of ink afforded by the surfactant. However, the
simple addition of a surfactant in a larger amount as above cannot
prevent mixing of different colors of inks at the border of colors
even though it improves the ink fixation. Moreover, it augments
penetration of ink toward the back face of the paper, which lowers
color density on the paper face, or causes nonuniform dyeing of a
fiber layer on the paper surface, resulting in irregularity of
color density in solid printing area and deterioration of image
quality.
Furthermore, feathering and ink fixation on a plain paper are
improved by use of strongly alkaline ink (see Japanese Patent
Application Laid-Open No. 56-57862, etc.), or by use of a specific
kind of ink (see Japanese Patent Application Laid-Open No. 56-5871,
etc.). These inks, however, do not always prevent bleeding
satisfactorily, and even in the case where the bleeding is
relatively slight, the feathering is conspicuous (not satisfying
the aforementioned requirement (1) of the prior art) or ejection
failure is liable to occur (not satisfying the aforementioned
requirement (6) of the prior art). As above, no color ink has been
obtained which satisfies all the above requirements and gives high
quality of an image with high speed on plain paper.
SUMMARY OF THE INVENTION
The present invention intends to provide an ink for ink-jet
recording which is capable of forming a color image of high quality
at high and uniform color density on a usual recording medium such
as plain paper without feathering or ink-bleeding, and especially
without mixing of different colors of inks at the color border.
The present invention also intends to provide an ink-jet recording
method, and an ink-jet recording apparatus employing the above
ink.
According to a first aspect of the present invention, there is
provided an ink for ink-jet recording which contains a dye and
water, and further comprises the components (a), (b), and (c)
below:
(a) at least one surfactant selected from the group consisting of
higher alcohol-ethylene oxide adducts represented by General
Formula [1], alkylphenol-ethylene oxide adducts represented by
General Formula [2], ethylene oxide-propylene oxide copolymers
represented by General Formula [3], and acetylene glycol-ethylene
oxide adducts represented by General Formula [4], at a content of
from 0.1 to 20% by weight based on the total weight of the ink;
where R is alkyl, and n is an integer; ##STR4## where R is alkyl,
and n is an integer; ##STR5## where R is alkyl or hydrogen, and n
and l are respectively an integer; ##STR6## where m and n are
respectively an integer; (b) thiodiglycol; and
(c) urea or an derivative thereof.
According to a second aspect of the present invention, there is
provided an ink-jet recording method which conducts recording on a
recording medium with droplets of ink, which comprises dye, water,
and the aforementioned components (a), (b), and (c).
According to a third aspect another aspect of the present
invention, there is provided a color ink-jet recording method which
conducts recording by ejecting droplets of inks of two or more
colors to adjacent or superposed positions on a recording medium,
using the ink comprising a dye, water and the aforementioned
components (a), (b), and (c).
According to a fourth aspect of the present invention, there is
provided an ink which comprises a dye, a water-soluble organic
solvent, water, and a compound of the formula; ##STR7## where
R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are respectively hydrogen,
an alkyl or alkenyl group of 1 to 4 carbon atoms, or a substituted
or unsubstituted phenyl group; and m+n is ranging from 0 to 50; and
l is a number of 2 or more.
According to a fifth aspect of the present invention, there is
provided an ink-jet recording method which conducts recording with
droplets of ink on a recording medium, using the ink comprising a
dye, water-soluble organic solvent, water, and a compound
represented by General Formula [5] above.
According to a sixth aspect of the present invention, there is
provided a color ink-jet recording method which conducts recording
by ejecting droplets of ink of two or more colors to adjacent or
superposed positions on a recording medium, using the ink
comprising a dye, water and the aforementioned compound represented
by General Formula [5] above.
According to a seventh aspect of the present invention, there is
provided a recording unit comprising an ink container portion for
holding ink and a head for ejecting the ink as ink droplets, in
which the ink is the one specified in the above first or fourth
aspect of the present invention.
According to a eighth aspect of the present invention, there is
provided an ink cartridge comprising an ink container portion for
holding ink, in which the ink is the one specified in the above
first or fourth aspect of the present invention.
According to ninth aspect of the present invention, there is
provided an ink-jet recording apparatus comprising the recording
unit of the seventh aspect of the present invention, wherein the
ink of the above first or fourth aspect of the present invention is
employed.
According to a tenth aspect of the present invention, there is
provided an ink-jet recording apparatus, comprising an ink
cartridge of the eighth aspect of the present invention, and a
recording head.
According to an eleventh aspect of the present invention, there is
provided a color ink-jet recording method in which droplets of two
or more color inks are ejected in accordance of pulse signal to
adjacent or superposed positions on a recording medium, and in
which the ink comprises a nonionic surfactant in an amount of from
1.0 to 20.0% by weight, the ink ejected for one pulse is in an
amount of from 10 to 70 pl, and the feathering rate (A) defined by
Equation [I] is in the range of from 2.5 to 3.5:
where B is a diameter (.mu.m) of a dot formed on plain paper, and C
is a diameter (.mu.m) of the ejected ink droplet.
According to a twelfth aspect of the present invention, there is
provided color ink-jet recording apparatus which conducts recording
by ejecting droplets of two or more color inks onto adjacent or
superposed positions on a recording medium, said apparatus
comprises a recording means for conducting recording mode, by use
of an ink containing a nonionic surfactant in an amount of from 1.0
to 20.0% by weight, by ejecting the ink for one pulse in an amount
of from 10 to 70 pl to form ink dots at the feathering rate (A)
defined by Equation [I] is in the range of from 2.5 to 3.5:
where B is a diameter (.mu.m) of a dot formed on plain paper, and C
is a diameter (.mu.m) of the ejected ink droplet.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an example of the pattern of dotting of different
color inks.
FIG. 2 shows another example of the pattern of dotting of different
color inks.
FIG. 3 is a longitudinal cross-sectional view of a head portion of
an ink-jet recording apparatus of the present invention.
FIG. 4 is a transverse cross-sectional view of a head portion of an
ink-jet recording apparatus of the present invention.
FIG. 5 is a perspective view of a head portion of an ink-jet
recording apparatus of the present invention.
FIG. 6 is a perspective view of an ink-jet recording apparatus of
the present invention.
FIG. 7 is a longitudinal sectional view of an ink cartridge of the
present invention.
FIG. 8 is a perspective view of a recording unit of the present
invention.
FIG. 9 is a perspective view of a recording portion in which a
plurality of recording heads are arranged and which was used in an
example of the present invention.
FIG. 10 is a perspective view of another recording head used in the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The inventors of the present invention have studied comprehensively
a method of color image formation which does not causes bleeding of
ink and gives a uniform color image without irregularity of colors.
As the result, it has been found as a first invention that an ink
containing the components (a), (b), and (c) below is extremely
effective:
(a) at least one surfactant selected from the group consisting of
higher alcohol-ethylene oxide adducts represented by General
Formula [1], alkylphenol-ethylene oxide adducts represented by
General Formula [2], ethylene oxide-propylene oxide copolymers
represented by General Formula [3], and acetylene glycol-ethylene
oxide adducts represented by General Formula [4], at a content of
from 0.1 to 20% by weight;
where R is alkyl, and n is an integer; ##STR8## where R is alkyl,
and n is an integer; ##STR9## where R is alkyl or hydrogen, and n
and l are respectively an integer; ##STR10## where m and n are
respectively an integer; (b) thiodiglycol; and
(c) urea or a derivative thereof.
As the further result of the study, it has been found as a second
invention that an ink comprising the compound represented by
General Formula (5) below is extremely effective: ##STR11## where
R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are respectively hydrogen,
an alkyl or alkenyl group of 1 to 4 carbon atoms, or a substituted
or unsubstituted phenyl group; and m+n is ranging from 0 to 50; and
l is a number of 2 or more.
The inks of the first invention and the second invention are
effective for formation of uniform images without bleeding or color
irregularity presumably from the reasons below.
The most important factor which affects prevention of ink bleeding
and uniformity of color of recorded images is considered to be the
wettability of a recording medium by the ink, or a wetting power of
the ink on the recording medium. Among the recording media, plain
paper especially has fibers exposed on the recording surface, and
the fiber density on the surface is not uniform. At the portion
where the fiber density is high, the ink fixation is slow, whereby
ink bleeds or the color of an image becomes irregular. The ink
which has a sufficient wetting power is considered to be fixed
uniformly irrespectively of the paper fiber density, and to be free
from bleeding and color irregularity. Further, the ink which has
excellent wetting power is considered to form precisely circular
dots with uniformity of color, thereby providing images of higher
quality.
The first invention of the present invention will be described in
detail.
The wetting power of the ink relates closely to the interaction
between the ink and the recording material at the interface.
Addition of a surfactant generally decreases the interfacial
tension between the ink and the recording medium, and improves the
wetting power of the ink. In particular, the nonionic surfactant
having an ethylene oxide chain as the component (a) of the first
invention, when incorporated in the ink, the hydrophilic ethylene
oxide portion of the surfactant presumably orients toward the
recording medium to give a specific uniform wettability. On the
contrary, an ionic surfactant, which has a hydrophilic portion
which has less affinity with the recording medium than the nonionic
surfactant, does not exhibit such effect.
The ethylene oxide addition type nonionic surfactant in the present
first invention is preferably added in an amount of from 0.1 to
20%, more preferably from 0.1 to 5% by weight based on the weight
of the ink. The wetting power is not sufficient at the amount of
surfactant of less than 0.1% by weight, while, addition of the
surfactant in an amount exceeding 20% by weight does not greatly
improve the wetting property, and is disadvantageous in production
cost and ink reliability.
The addition number of the ethylene oxide unit, the hydrophilic
portion, in the ethylene oxide addition type nonionic surfactant in
the present first invention is preferably in the range of from 4 to
20, more preferably from 4 to 10 in terms of "n" or "n+m" in
consideration of the affinity of the ethylene oxide moiety with the
recording medium and orientation thereon. At the value of "n" or
"n+m" of less than 4, the solubility of the surfactant is not
sufficient to achieve the effect of the present invention, while at
the value of more than 20, the excessive ethylene oxide is not
necessarily effective and leads to slightly unstable ink
ejection.
The medium for the aforementioned ethylene oxide addition type
nonionic surfactant is described below.
Generally, the ethylene oxide addition type nonionic surfactant is
inconvenient for stabilization of ink ejection because of its
relatively high viscosity in consideration of ejection
stabilization. Therefore, an additional water-soluble organic
solvent has been studied to improve the ink ejection without
impairing the effects of the present invention. Consequently,
thiodiglycol has been found to be satisfactory. The failure of ink
ejection is caused generally by rise of viscosity resulting from
vaporization of water at the nozzle. The use of thiodiglycol is
considered to reduce the rise of the viscosity more than other
solvents, thereby improving the ejection property. However, single
use of thiodiglycol is not sufficiently effective yet for ejection
stabilization. After comprehensive study, it has been found that
the combined use of thiodiglycol and urea or a derivative of urea
improves greatly the ink ejection property. Presumably, the
interaction between the thiodiglycol and urea or a urea derivative
suppresses the rise of the viscosity, specifically, and the
dissolution of a dye is improved. The thiodiglycol and a urea
derivative-thiourea derivative are used respectively in an amount
of from 1 to 30% by weight.
The amount of water used in the present first invention is
preferably in the range of from 50 to 85%, more preferably from 55
to 75% by weight. If the amount of water is less than 50%, the
viscosity of the ink is relatively high, and the ejection stability
tends to be relatively lower, even when thiodiglycol or urea or a
derivative thereof is used concurrently. If the amount of water is
more than 85%, the ethylene oxide portion, which is the hydrophilic
portion of the ethylene oxide addition type nonionic surfactant, is
relatively free, resulting in less orientation thereof and less
uniformity.
The water-soluble organic solvents constituting the ink of the
present first invention include polyalkylene glycols such as
polyethylene glycol, and polypropylene glycol; alkylene glycols
having 2 to 6 carbon atoms such as ethylene glycol, propylene
glycol, butylene glycol, triethylene glycol, hexylene glycol, and
diethylene glycol; glycerine; 1,2,6-hexanetriol; lower alkyl ethers
of polyhydric alcohols such as ethylene glycol methyl ether,
diethylene glycol methyl (or ethyl) ether, and triethylene glycol
monomethyl (or ethyl) ether; alcohols such as methyl alcohol, ethyl
alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol,
sec-butyl alcohol, t-butyl alcohol, isobutyl alcohol, benzyl
alcohol, and cyclohexanol; amides such as dimethylformamide, and
dimethylacetamide; ketones and ketone alcohols such as acetone, and
diacetone alcohol; ethers such as tetrahydrofuran, and dioxane; and
nitrogen-containing heterocyclic ketones such as
N-methyl-2-pyrrolidone, 2-pyrrolidone,
1,3-dimethyl-2-imidazolidinone.
The water-soluble organic solvent may be incorporated in such an
amount that ink-bleeding is not caused, and the ejection property
is not impaired. Among the above solvents, preferred are ethylene
glycol, triethylene glycol, hexylene glycol, diethylene glycol,
glycerin, ethyl alcohol, isopropyl alcohol, cyclohexanol, and so
forth. The solvent preferably is contained in an amount of from 1
to 15% by weight based on the total weight of the ink.
The dyes employed in the present invention include direct dyes,
acid dyes, reactive dyes, disperse dyes, vat dyes, and the like.
The content of the dye is decided depending on the kinds of the
liquid medium components and the required properties of the ink,
and is generally in the range of from 0.5 to 15%, preferably from 1
to 7% by wight based on the total weight of the ink.
The main constituents of the ink of the present first invention are
described above. Other additives may be incorporated provided that
the objects of the invention are achievable. The additive includes
viscosity-adjusting agents such as polyvinyl alcohol, celluloses,
and water-soluble resins; pH-controlling agents such as
diethanolamine, triethanolamine, and buffer solutions; fungicides;
and so forth. To the ink of an electrically chargeable type used
for ink-jet recording in which the ink droplets are charged, a
resistivity-adjusting agent is added, such as lithium chloride,
ammonium chloride, and sodium chloride.
The second invention will be described in detail.
Generally, inks which contain a compound having one triple bond in
the molecule give uniform color. However, the ink of the present
second invention provides much more excellent uniformity of color
than the above ink containing a compound having one triple
bond.
Presumably, the compound which is represented by General Formula
[5] having two or more triple bonds and contained in the ink of the
present second invention has high electron density in the molecule
and has a rigid hydrophobic portion (triple bond-containing
portion), causing little a free change in structure in comparison
with the compound having one triple bond, whereby the compound of
General Formula [5] orients regularly to the surface of the ink,
and interacts effectively with the recording medium at the
interface to exhibit high wettability.
The ink of the present second invention contains the compound of
General Formula [5] below in an amount of preferably from 0.001 to
20%, more preferably from 0.001 to 5% by weight based on the total
weight of the ink, and the number of m+n in the formula is in the
range of from 0 to 50. ##STR12##
Specific examples of the compound of General Formula [5] are shown
below without limiting the compound thereto in any way.
##STR13##
The liquid medium constituting the ink of the present second
invention may be a plain water-soluble organic solvent. The
water-soluble solvents include polyalkylene glycols such as
polyethylene glycol, and polypropylene glycol; alkylene glycols
having 2 to 6 carbon atoms such as ethylene glycol, propylene
glycol, butylene glycol, triethylene glycol, hexylene glycol,
diethylene glycol, and thiodiglycol; glycerine; 1,2,6-hexanetriol;
lower alkyl ether of polyhydric alcohols such as ethylene glycol
methyl ether, diethylene glycol methyl (or ethyl) ether, and
triethylene glycol monomethyl (or ethyl) ether; alcohols such as
methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol,
n-butyl alcohol, sec-butyl alcohol, t-butyl alcohol, isobutyl
alcohol, benzyl alcohol, and cyclohexanol; amides such as
dimethylformamide, and dimethylacetamide; ketones and ketone
alcohols such as acetone, and diacetone alcohol; ethers such as
tetrahydrofuran, and dioxane; and nitrogen-containing heterocyclic
ketones such as N-methyl-2-pyrrolidone, 2-pyrrolidone,
1,3-dimethyl-2-imidazolidinone.
Among the above water-soluble solvents, preferred are ethylene
glycol, triethylene glycol, hexylene glycol, diethylene glycol,
glycerine, thiodiglycol, ethyl alcohol, isopropyl alcohol,
cyclohexanol, and so forth. The solvent is preferably contained at
a content of from 1 to 35% based on the total weight of the
ink.
The dyes employed in the present invention include direct dyes,
acid dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, and
the like. The content of the dye is decided depending on the kinds
of the liquid medium components and the required properties of the
ink, and is generally in the range of from 0.5 to 15%, preferably
from 1 to 7% by weight based on the total weight of the ink.
The main constituents of the ink of the present second invention
are described above. Other additives may be added provided that the
objects of the invention are achievable. The additives include
clogging preventing agents such as urea and its derivatives;
viscosity-adjusting agents such as polyvinyl alcohol, celluloses,
and water-soluble resins; pH-controlling agents such as
diethanolamine, triethanolamine, and buffer solutions; fungicides;
surfactants, and so forth. To the ink of an electrically chargeable
type used for ink-jet recording in which the ink droplets are
charged, an resistivity-adjusting agent is preferably incorporated
such as lithium chloride, ammonium chloride, and sodium
chloride.
The inks of the first invention and the second invention are
suitable for ink-jet recording in which the ink droplets are
ejected by action of thermal energy. However, the inks are
naturally useful also for other types of ink-jet recording and for
general writing implements.
The recording apparatus suitable for recording with the ink of the
present first invention and the present second invention includes
those in which thermal energy is given to the ink in a chamber in a
recording head in correspondence with recording signals, and
thereby ink droplets are formed.
The third invention will be described below in detail.
The inventors of the present invention have noticed the necessary
conditions shown below for forming color images in high quality on
plain paper.
When different color inks are dotted in a pattern as shown in FIG.
1, the different color inks are less liable to be mixed at the
boundaries of the dotted colors, even if the adjacent color is
dotted subsequently in a short time. In this case, however,
disadvantages may be caused such that the central portion
surrounded by dots becomes blank, which may cause decrease of color
density, and a slight shift of the ejected ink droplet from the
aimed impact point may increase the area of the blank portion.
On the contrary, if the ink is dotted as shown in FIG. 2 by
satisfying the Equation [II] below, the above disadvantage is
significantly reduced, and excellent images are obtained: ##EQU1##
where B is a dot diameter (.mu.m) formed on plain paper, and D is a
recording density (dots/mm). In this method of dotting, however,
different color inks are necessarily mixed as shown by the shadowed
portions in FIG. 2, and thereby mixing of the different color inks
is liable to occur.
In FIGS. 1 and 2, C, M and Y means a droplet of cyan ink, magenta
ink and yellow ink, respectively.
The inventors have investigated the method of preventing the mixing
of different color inks at the color boundaries with the high
quality of image being maintained regarding the case where the inks
are dotted according to Equation [II]. As the result, it has been
found that the above problem is solved by adjusting the feathering
rate (A) shown by Equation [I] below on plain paper to be in the
range of from 2.5 to 3.5.
where B is a dot diameter (.mu.m) formed on plain paper, and C is a
diameter (.mu.m) of the ejected ink droplet. At the feathering rate
of less than 2.5, the ink droplet attached on the paper surface
spreads less and the ink layer does not become thin, thereby
different colors of inks mixed at the boundaries of colors when
inks are dotted under the conditions shown in FIG. 2. On the
contrary, at the feathering rate of more than 3.5, the ink droplet
spreads excessively and the edge of the dot becomes unclear, thus
providing images of low quality.
In order to control the feathering ratio in the range of from 2.5
to 3.5, a nonionic surfactant is incorporated into the ink in an
amount of from 1 to 20%, more preferably from 3 to 10% by weight.
With the amount of the nonionic surfactant of less than 1% by
weight, the feathering ratio becomes less than 2.5, thus causing
color ink mixing at the color border, while with the amount of the
nonionic surfactant of more than 20% by weight, the feathering rate
becomes more than 3.5, thus the image quality is liable to become
low.
Simple use of surfactant in a large amount gives rise to
disadvantages of lowering of color density and image quality caused
by excessive penetration of ink droplets toward the back face of
the paper sheet, and of nonuniformity of color density in a solid
print portion caused by nonuniform dyeing of the fiber layer at the
paper surface. The inventors of the present invention have found
that color image recording with high quality is practicable when a
nonionic surfactant is used as the surfactant and when printing is
carried out using the ink containing it in an amount of from 1 to
20% by weight with controlling the amount of ink ejection in the
range of from 10 to 70 pl, preferably from 20 to 50 pl per one
nozzle for one pulse. The present third invention has been
accomplished on the basis of the above two findings.
The nonionic surfactant does not have selective affinity to a fiber
layer on the surface of paper, whereby uniform dyeing is achievable
and nonuniformity of color density is avoided. The ink for the
color recording method of the present invention contains a
surfactant in a large amount. Therefore, if the ink droplets are
ejected in an amount of more than 70 pl per one nozzle for one
pulse, the amount of the ink exceeds the absorbable and fixable
limit of the fiber layer on the paper surface, causing penetration
of ink into a pore layer under the fiber layer owing to the
penetrating power of the surfactant, thus resulting in
deterioration of image quality owing to lowered color density and
irregular feathering. Accordingly the amount of the ink ejection
has to be controlled to be in the range of from 10 to 70 pl per
pulse.
The nonionic surfactants employed in the present third invention
include polyoxyethylene alkyl ethers, polyoxyethylene phenyl
ethers, polyoxyethylene-polyoxypropylene glycols,
polyoxyethylene-polyoxypropylene alkyl ethers, polyethylene oxide
adducts of acetylene glycol, etc. Of these, preferred are
nonylphenyl ether-ethylene oxide adducts, ethylene oxide-propylene
oxide copolymer (EO-PO adducts), acetylene glycol-polyethylene
oxide adducts; particularly preferred are acetylene
glycol-polyethylene oxide adducts (acetylene glycol-EO adducts)
represented by the structural formula below. ##STR14## where
m+n=10.
The water-soluble organic solvents employed in addition to the
nonionic surfactant in the present third invention include amides
such as dimethylformamide, and dimethylacetamide; ketones such as
acetone; ethers such as tetrahydrofuran, and dioxane; polyalkylene
glycols such as polyethylene glycol, and polypropylene glycol;
alkylene glycols having 2 to 6 carbon atoms such as ethylene
glycol, propylene glycol, butylene glycol, triethylene glycol,
thiodiglycol, hexylene glycol, and diethylene glycol; glycerin;
1,2,6-hexanetriol; lower alkyl ether of polyhydric alcohols such as
ethylene glycol methyl (or ethyl) ether, diethylene glycol methyl
(or ethyl) ether, and triethylene glycol monomethyl (or ethyl)
ether; N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone,
triethanolamine, sulfolane, dimethylsulfoxide, and so forth.
The clogging-preventing agents include urea and derivatives of
urea, sulfonamides, and the like.
The dyes employed in the present invention include direct dyes,
acid dyes, reactive dyes, disperse dyes, vat dyes, and the like.
The content of the dye is decided depending on the kinds of the
liquid medium components and the required properties of the ink,
and is generally in the range of from 0.5 to 15%, preferably from 1
to 7% by weight based on the total weight of the ink.
The main constituents of the ink of the present third invention are
described above. Other additives may be added provided that the
objects of the invention are achievable. The additives include
viscosity adjusting agents such as polyvinyl alcohol, celluloses,
and water-soluble resins; pH-controlling agents such as
diethanolamine, triethanolamine, and buffer solutions; fungicides;
and so forth. To formulate the ink of an electrically chargeable
type used for ink-jet recording in which the ink droplets are
charged, an resistivity-adjusting agent is preferably added such as
lithium chloride, ammonium chloride, and sodium chloride.
The recording method of the present third invention is particularly
suitable for ink-jet recording in which ink droplets are ejected by
the action of thermal energy, but it is also applicable to other
ink-jet recording methods.
A recording apparatus is described below, which produces ink
droplets by thermal energy and is suitable for practicing the
recording of the present first invention, the present second
invention, and the present third invention. The present invention
is suitable for the recording system in which recording signal is
applied to a recording ink in a recording head and ink droplets are
ejected by the action of the generated thermal energy. The
construction of the recording head, which is the main portion of
the apparatus, is shown in FIGS. 3, 4, and 5.
A head 13 is constructed by bonding a plate of glass, ceramics, or
plastics having an ink flow path to a heat-generating head 15. (The
head is shown in the drawing, but the invention is not limited to
this.) The heat-generating head 15 is constituted of a protection
layer 16 formed of silicon oxide or the like, aluminum electrodes
17-1 and 17-2, a heat-generating resistance layer 18 formed of
nichrome or the like, a heat accumulation layer 19, and a substrate
plate 20 made of aluminum or the like having a high heat-radiating
property.
Ink 21 reaches the ejection orifice 22, forming a meniscus 23 by
action of pressure P not shown in the drawing.
On application of an electric signal to the electrodes 17-1 and
17-2, the region designated by a symbol "n" on the heat-generating
head 15 generates abruptly heat to form a bubble in the portion of
the ink 21 contacting therewith. The pressure generated by the
bubble pushes out the meniscus 23 and ejects the ink 21 from the
orifice 22 in a form of ink droplets 24, and the ink droplets are
ejected to a recording medium 25. FIG. 5 shows a rough sketch of a
multiple recording head constructed by juxtaposing a multiplicity
of heads shown in FIG. 3. The recording head is prepared by bonding
a glass plate 27 having a plurality of flow paths to a
heat-generating head 28 similar to the one shown in FIG. 3.
Incidentally, FIG. 3 is a cross-sectional view of the head 13 along
an ink flow path, and FIG. 4 is a cross-sectional view of the head
at the line A-B in FIG. 3.
FIG. 6 illustrates an example of the ink-jet recording apparatus
having such a head mounted therein.
In FIG. 6, a blade 61 as a wiping member is held at one end by a
blade-holding member, forming a fixed end in a shape of a
cantilever. The blade 61 is placed at a position adjacent to the
recording region of the recording head, and is constituted such
that it moves in the direction perpendicular to the moving
direction of the recording head to come into contact with the
ejection nozzle face to cap the nozzles. An ink absorption member
63 is provided at a position adjacent to the blade 61, and is held
so as to protrude into the moving path of the recording head in a
manner similar to that of the blade 61. The aforementioned blade
61, the cap 62, and the absorption member 63 constitute an
ejection-recovery section 64. The blade 61 and the absorption
member 63 remove water, dust, and the like from the ink ejecting
nozzle face.
A recording head 65 has an ejection energy-generating means for
ejection, and conducts recording by ejecting ink onto a recording
medium opposing to the ejection nozzle face. A carriage 66 is
provided for supporting and moving the recording head 65. The
carriage 66 is engaged slideably with a guide rod 67. A portion of
the carriage 66 is connected (not shown in the drawing) to a belt
69 driven by a motor 68, so that the carriage 66 is movable along
the guide rod 67 to the recording region of the recording head 65
and the adjacent region thereto.
A paper delivery portion 51 for delivery of a recording medium and
a paper delivery roller 52 driven by a motor (not shown in the
drawing) delivers the recording medium to the position opposing to
the ejecting nozzle face of the recording head, and the recording
medium is discharged with the progress of the recording to a paper
discharge portion provided with paper-discharging rollers 53.
In the above constitution, when the recording head 65 returns to a
home position at the completion of the recording or other timing,
the cap 62 of the ejection-recovery portion 64 is positioned out of
the moving path of the recording head 65, and the blade 61 is made
to protrude into the moving path. Therefore, the ejecting nozzle
face of the recording head 65 is wiped therewith. The cap 62 moves
to protrude toward the moving path of the recording head when the
cap 62 comes into contact with the ejecting nozzle face of the
recording head for capping.
At the time when the recording head 65 moves from the home position
to the record-starting position, the cap 62 and the blade 61 are at
the same position as in the above-mentioned wiping time, so that
the ejection nozzle face of the recording head is wiped also in
this movement.
The recording head moves to the home position not only at the end
of the recording and at the time of ejection recovery, but also at
a predetermined interval during movement for recording in the
recording region. By such movement, the wiping is conducted.
FIG. 7 illustrates an example of the ink cartridge that contains
ink to be supplied through an ink supplying member such as a tube.
The ink container portion 40, for example an ink bag, contains an
ink to be supplied, and has a rubber plug 42 at the tip. By
inserting a needle (not shown in the drawing) into the plug 42, the
ink in the ink bag 40 becomes suppliable. An ink absorption member
44 absorbs waste ink.
The ink container portion has preferably a liquid-contacting
surface made of polyolefin, particularly preferably made of
polyethylene.
The ink-jet recording apparatus used in the present invention is
not limited to the above-mentioned one which has separately a head
and an ink cartridge. Integration thereof as shown in FIG. 8 may
suitably be used.
In FIG. 8, a recording unit 70 houses an ink container portion such
as an ink absorption member, and the ink in the ink absorption
member is ejected from a head 71 having a plurality of orifices.
The ink absorption member may be made of a material such as
polyurethane. An air-communication opening 72 is provided to
communicate the interior of the cartridge with the open air. The
recording unit 70 may be used in place of the recording head shown
in FIG. 6, and is readily mountable to and demountable from the
carriage 66.
An ink-jet recording apparatus which ejects ink droplets by action
of thermal energy to the ink is exemplified above. The present
invention, however, is applicable also to other ink-jet recording
apparatuses such as the one of a piezo type which employs a
piezoelectric element.
For practicing the recording according to the present invention, a
recording apparatus, for example, is used which has four (in
number) of recording heads shown in FIG. 5 juxtaposed on a
carriage. FIG. 9 shows an example of the apparatus. Recording heads
81, 82, 83, and 84 are recording heads ejecting respectively
recording inks of yellow, magenta, cyan, and black. The heads are
mounted on the aforementioned recording apparatus, and eject
respective color inks in accordance with recording signals. The
apparatus in FIG. 9 employs four recording heads, but the present
invention is not limited thereto. One recording head may be
constructed to eject all of the yellow, magenta, cyan, and black
inks as shown in FIG. 10.
The present invention is described in more detail by reference to
the Examples and Comparative Examples. In the description, the
terms "parts" and "%" are based on weight unless otherwise
mentioned. Hereinafter, the ethylene oxide adduct is simply
referred to as "EO adduct".
The dyes and liquid medium in an amount (parts) shown below are
employed in the Example and Comparative Example to provide each 100
parts of inks, respectively.
EXAMPLE 1
__________________________________________________________________________
(Dyes) Black: C.I. Food Black 2 2 parts Dye A of Formula below 1.2
parts Dye B of Formula below 0.8 part Yellow: C.I. Direct Yellow 86
2.5 parts Cyan: C.I. Direct Blue 199 3.5 parts Magenta: Dye C of
Formula below 3.5 parts (Liquid medium) Thiodiglycol 7.5 parts Urea
7.5 parts Glycerin 7.5 parts Higher alcohol-EO adduct (n = 15)* 1
part Pure water balance
__________________________________________________________________________
*(Higher alcoholEO adduct: BO15TX (made by Nikko Chemicals K.K.) is
used.
Dye A ##STR15## Dye B ##STR16## Dye C ##STR17##
__________________________________________________________________________
Each of the four color compositions was stirred sufficiently, and
was filtered under pressure through a Fluoropore Filter (trade
name, made by Sumitomo Electric Industries, Ltd.) having a pore
diameter of 0.22 .mu.m to prepare the ink of the present invention.
The respective inks were introduced into a color ink-jet printer
BJC-820J (trade name, made by Canon K.K.) which conducts recording
by forming ink droplets by applying thermal energy to the inks in
the recording heads, and recording was conducted on commercial
paper sheets for copying (Canon NP Dry SK), and bond paper sheets
(Plover Bond Paper PB).
Evaluation was made as described below. The results are shown in
Table 1.
(1) Bleeding:
Color samples were prepared by printing such that different colors
are adjacent to each other, and the occurrence of bleeding was
evaluated by the standard below. The evaluation was made for seven
colors: black, yellow, cyan, and magenta; and red, green, and blue
formed by dotting in superposition of two colors taken from the
colors of yellow, cyan, and magenta.
o : No bleeding is observed at every boundary.
.DELTA. : Bleeding is remarkable at the boundaries of red, green,
and blue where a larger amount of ink is applied.
x : Bleeding is remarkable at nearly all the boundaries.
(2) Color uniformity:
Uniformity at solid color print portions are examined visually.
o : Solid color print is completely uniform without
irregularity.
.DELTA. : Nonuniformity is remarkable at the portion where fiber
density is high.
x : Color irregularity is much more remarkable.
(3) Occurrence of feathering:
Three hundred dots are printed continuously on a commercial paper
sheet for copying and a commercial bond paper sheet such that the
dots are not brought into contact with each other. The dotted ink
are dried in the air for 24 hours at room temperature. Irregular
shape and irregular feathering of dots are counted under a
microscope. The evaluation is made by the percentage of the counted
dot number according to the standard below:
.circleincircle. : not more than 10%
o : 11% to 30%
.DELTA. : 31% to 50%
x : not less than 51%
(4) Ejection property:
The ink to be tested is filled in the printer, and alphabet and
numeral letters are printed continuously for 10 minutes with the
printer. Thereafter, the printer is left standing without capping
the nozzles. After 10 minutes of intermission of the printing, the
printing is started again. The ejection property is evaluated from
scratches and unsharp edges in printed letters after restarting the
printing.
o : No scratch and no unsharp edge is observed from the first
letter.
.DELTA. : A part of the first letter is scratched or unsharp.
x : The first letter cannot be printed.
(5) Storage stability:
The ink is placed in an amount of 100 ml in a heat-resistant glass
bottle, stoppered tightly, and stored in a thermostatic chamber at
60.degree. C. After 2 months of storage, the ink is used for
printing, and evaluated.
o : No abnormality is observed.
x : Failure of discharge, or irregularity or discoloration of
printed letters is observed.
(6) Anti-Clogging (crusting recovery):
The ink to be tested is filled in the printer, and alphabet and
numeral letters are printed continuously for 10 minutes with the
printer. Thereafter, the printer is left standing without capping
of the nozzles. After one month of intermission of the printing,
ejection recovery operation was conducted. The evaluation was made
by counting the required number of times of the ejection recovery
operations for carrying out normal printing.
o : Printing is normal after 1 to 5 times of ejection recovery
operation.
.DELTA. : Printing is normal after 6 to 10 times of ejection
recovery operation.
x : Printing is normal after 11 or more times of ejection recovery
operation.
EXAMPLES 2 TO 5
In the respective Examples, the kind and the amount of the dyes
used were as below:
______________________________________ (Dyes for Examples 2 to 4)
Black: C.I. Food Black 2 2 parts Dye A 1.2 parts Dye B 0.8 part
Yellow: C.I. Direct Yellow 86 2.5 parts Cyan: C.I. Direct Blue 199
3.5 parts Magenta: Dye C 3.5 parts (Dyes for Example 5) Black: C.I.
Food Black 2 2 parts Dye A 1.2 parts Dye B 0.8 part Yellow: C.I.
Direct Yellow 86 2.5 parts Cyan: C.I. Acid Blue 9 3.0 parts
Magenta: Dye C 3.5 parts ______________________________________
The liquid mediums used in the respective Examples were as
below:
______________________________________ (Liquid medium for Example
2) Thiodiglycol 7.5 parts Urea 7.5 parts Glycerine 7.5 parts
Nonylphenyl ether-EO adduct 5 part (n = 9 to 10) Pure water balance
(Liquid medium for Example 3) Thiodiglycol 7.5 parts Thiourea 7.5
parts Glycerine 7.5 parts Ethylene oxide-propylene oxide 15 parts
copolymer (n = 10, L = 7) Pure water balance (Liquid medium for
Example 4) Thiodiglycol 7.5 parts Urea 7.5 parts Glycerine 7.5
parts Acetylene glycol-EO adduct 5 parts (n + m = 10) Pure water
balance (Liquid medium for Example 5) Thiodiglycol 7.5 parts Urea
7.5 parts Glycerine 7.5 parts Acetylene glycol-EO adduct 1 parts (n
+ m = 4) Pure water balance
______________________________________
In the above, as acetylene glycol-EO adduct, Acetylenol (made by
Kawaken Fine Chemical K.K.), as the nonylphenyl ether-EO adduct,
Emulgen 909 (made by Kao Corporation), and as the ethylene
oxide-propylene oxide copolymer, Karpole MH-50 (made by Asahi Denka
Kogyo K.K.) are used, respectively.
The respective inks were prepared with the dye and the liquid
medium shown above in the same manner as in Example 1. Printing
properties, ejection properties, and the storage stability of the
inks were evaluated in the same manner as in Example 1. The results
are shown in Table 1.
COMPARATIVE EXAMPLES 1 TO 5
In the respective Comparative Examples, the kind and the amount of
the dyes were are as below:
______________________________________ (Dyes for Comparative
Examples 1 to 5) ______________________________________ Black: C.I.
Food Black 2 2 parts Dye A 1.2 parts Dye B 0.8 part Yellow: C.I.
Direct Yellow 86 2.5 parts Cyan: C.I. Direct Blue 199 3.5 parts
Magenta: Dye C 3.5 parts ______________________________________
The liquid mediums used in the respective Comparative Examples were
as below:
______________________________________ (Liquid medium for
Comparative Example 1) Thiodiglycol 7.5 parts Urea 7.5 parts
Glycerine 7.5 parts Pure water balance (Liquid medium for
Comparative Example 2) Thiodiglycol 15 parts Glycerine 7.5 parts
Acetylene glycol-EO adduct 5 parts (n + m = 10) Pure water balance
(Liquid medium for Comparative Example 3) Urea 10 parts Glycerine
12.5 parts Acetylene glycol-EO adduct 5 parts (n + m = 10) Pure
water balance (Liquid medium for Comparative Example 4)
Thiodiglycol 7.5 parts Urea 7.5 parts Glycerine 7.5 parts Anionic
surfactant (Neopelex 25, 7 parts made by Kao Corporation) Pure
water balance (Liquid medium for Comparative Example 5)
Thiodiglycol 7.5 parts Urea 7.5 parts Glycerine 7.5 parts Cationic
surfactant (Cation DDC-50, 5 parts made by Sanyo Chemical
Industries, Ltd.) Pure water balance
______________________________________
The respective inks were prepared with the dye and the liquid
medium shown above in the same manner as in Example 1. Printing
properties, ejection properties, and the storage stability of the
inks were evaluated in the same manner as in Example 1. The results
are shown in Table 1.
TABLE 1 ______________________________________ Evaluation (1) (2)
(3) item SK PB SK PB SK PB (4) (5) (6)
______________________________________ Examples 1 .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .smallcircle. 2
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. 3 .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .smallcircle. 4 .smallcircle. .smallcircle.
.smallcircle. .smallcircle. .circleincircle. .circleincircle.
.smallcircle. .smallcircle. .smallcircle. 5 .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .circleincircle.
.circleincircle. .smallcircle. .smallcircle. .smallcircle.
Comparative examples 1 x x x x .circleincircle. .circleincircle.
.smallcircle. .smallcircle. .smallcircle. 2 .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .circleincircle.
.circleincircle. .DELTA. .smallcircle. x 3 .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. x .smallcircle. .DELTA. 4 .smallcircle. .smallcircle.
.DELTA. x x x x x .DELTA. 5 .DELTA. x .DELTA. x .DELTA. .DELTA. x x
x ______________________________________ SK: Commercial paper for
copying PB: Plover Bond paper
EXAMPLES 6 TO 10 AND COMPARATIVE EXAMPLE 6
The dyes of black, cyan, magenta, and yellow, and the amount
thereof used in the respective Examples and Comparative Example are
as shown below:
______________________________________ (Dyes)
______________________________________ Black: C.I. Food Black 2 2
parts Dye A 1.2 parts Dye B 0.8 part Yellow: C.I. Direct Yellow 86
2.5 parts Cyan: C.I. Acid Blue 9 3.5 parts Magenta: Dye C 3.5 parts
______________________________________
EXAMPLE 6
______________________________________ Dye (black, yellow, cyan, or
in an amount as shown above magenta) Glycerine 8 parts Urea 5 parts
Thiodiglycol 8 parts Compound No. 1 1 part Pure water balance
______________________________________
The above ink compositions were respectively stirred sufficiently,
and filtered through a Fluoropore Filter (pore diameter 0.22 .mu.m,
trade name, made by Sumitomo Electric Industries, Ltd.) to prepare
inks of this Example.
EXAMPLE 7
______________________________________ Dye (black, yellow, cyan, or
in an amount as shown above magenta) Glycerine 8 parts Urea 5 parts
Thiodiglycol 8 parts Compound No. 2 16 part Pure water balance
______________________________________
The above ink compositions were prepared in the same manner as in
Example 6 to prepare inks of this Example.
EXAMPLE 8
______________________________________ Dye (black, yellow, cyan, or
in an amount as shown above magenta) Glycerine 8 parts Urea 5 parts
Thiodiglycol 8 parts Compound No. 3 0.5 part Cyclohexanol 1 part
Pure water balance ______________________________________
The above ink compositions were prepared in the same manner as in
Example 6 to prepare inks of this Example.
EXAMPLE 9
______________________________________ Dye (black, yellow, cyan, or
in an amount as shown above magenta) Glycerine 8 parts Urea 5 parts
Thiodiglycol 8 parts Compound No. 4 10 parts Pure water balance
______________________________________
The above ink compositions were prepared in the same manner as in
Example 6 to prepare inks of this Example.
EXAMPLE 10
______________________________________ Dye (black, yellow, cyan, or
in an amount as shown above magenta) Glycerine 8 parts Urea 5 parts
Thiodiglycol 8 parts Compound No. 5 5 parts Pure water balance
______________________________________
The above ink compositions were prepared in the same manner as in
Example 6 to prepare inks of this Example.
COMPARATIVE EXAMPLE 6
______________________________________ Dye (black, yellow, cyan, or
in an amount as shown above magenta) Glycerine 5 parts Urea 5 parts
Thiodiglycol 6 parts Pure water balance
______________________________________
The above ink compositions were prepared in the same manner as in
Example 6 to prepare inks of this Comparative Example.
<Evaluation >
The obtained inks of Examples 6 to 10 and Comparative Example 6
were used for printing on commercial paper sheets for copying
(Canon NP dry SK, and Prober bond paper PB). The recording
apparatus employed was similar to the one shown in FIG. 6. A color
image was formed by use of four recording heads shown in FIG. 9.
The recording heads were the same as the ones used in the ink-jet
printer BJC-820J (trade name, made by Canon K.K.). The recording
heads were driven under the driving conditions (or current-flowing
conditions) of the applied voltage of 28 V, the pulse width of 3.2
.mu.sec, and the drive frequency of 5 kHz.
The inks were evaluated regarding the evaluation items below. The
results are shown in Table 2.
(1) Bleeding:
Evaluated in the same manner as in Example 1.
(2) Uniformity of color:
Evaluated in the same manner as in Example 1.
(3) Rate of occurrence of feathering:
Three hundred dots are printed continuously on a commercial paper
sheet for copying and a commercial bond paper sheet such that the
dots are not brought into contact with each other. The dotted ink
is dried in the air for 24 hours at room temperature. Irregular
shape and irregular feathering of dots are counted under a
microscope. The evaluation is made by the percentage of the counted
dot number according to the standard below:
o : not more than 10%
.DELTA. : 10% to 20%
x : not less than 21%
(4) Storage stability:
Evaluated in the same manner as in Example 1.
(5) Anti-Clogging (crusting recovery):
Evaluated in the same manner as in Example 1.
TABLE 2 ______________________________________ Evaluation item (1)
(2) (3) (4) (5) ______________________________________ Example 6
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.smallcircle. Example 7 .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .smallcircle. Example 8 .smallcircle. .smallcircle.
.smallcircle. .smallcircle. .smallcircle. Example 9 .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .smallcircle. Example 10
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. Comparative x x .smallcircle. .smallcircle.
.smallcircle. example 6 ______________________________________
EXAMPLES 11 TO 18 AND COMPARATIVE EXAMPLES 7 TO 10
A color ink-jet recording apparatus which has four heads of the
same recording density for yellow, magenta, cyan, and black colors
and conducts recording by generation of ink droplets upon applying
thermal energy to the inks in the recording head was employed.
Three kinds of multiple-nozzle On-Demand type heads of recording
densities of 300 dpi (11.8 dots/mm), 360 dpi (14.2 dots/mm), and
400 dpi (15.7 dots/mm) were used.
The color inks (yellow, magenta, cyan, and black) for the
respective Examples were prepared by stirring sufficiently the
composition shown below and filtering the mixture through a
Fluoropore Filter (pore diameter of 0.22 .mu.m, trade name, made by
Sumitomo Electric Industries, Ltd.) under pressure.
______________________________________ (Dyes) Black: C.I. Food
Black 2 2 parts Dye A 1.2 parts Dye B 0.8 part Yellow: C.I. Direct
Yellow 86 2.5 parts Cyan: C.I. Direct Blue 199 3.5 parts Magenta:
Dye C 3.5 parts (Liquid medium) Thiodiglycol 7.5 parts Urea 7.5
parts Glycerine 7.5 parts Surfactant (as shown in Table 3) Pure
water balance ______________________________________
With the recording apparatus having the heads of recording density
shown in Table 3 mounted thereon, recording was conducted at the
ejection rate shown on commercial paper for copying (Canon NP dry
SK, and Xerox 4024), and commercial bond paper (Plover bond paper
sheet PB), and the recorded matter was evaluated.
The printed dot diameters and the feathering rates derived from the
dot diameter are shown in Table 3. The evaluation results are shown
in Table 4.
Recording was carried out under environmental conditions of the
temperature of 25.+-.2.degree. C. and the humidity of from 50 to
70% RH, and the printed samples were evaluated after they were left
for one day from the time they were printed.
The dot diameter ("B" in Equation [I]) in the present invention was
derived by image processing of printed dots by means of a CCD
camera to measure the area of the dot and conversion of the area to
a diameter of precise circle. The ink droplet diameter ("C" in
Equation [I]) was calculated from the equation below:
where V is the volume of a droplet (pl) ejected per one pulse.
The evaluation items:
(1) Bleeding,
(2) Uniformity of color, and
(3) rate of feathering were evaluated in the same manner as in
Example 1.
(4) Optical density:
The optical density of the printed matter was measured by MacBeth
Refractodensitometer RD-915 (made by MacBeth Co.). The average O.D.
values of yellow, magenta, cyan, and black were evaluated according
to the standard below:
o : not less than 1.0
.DELTA. : 0.9 to 1.0
x : not more than 0.9
TABLE 3
__________________________________________________________________________
Surfactant Dot Ink-drop Amount Ink- Concen- Recording diameter
diameter of running tration density (B) (C) ejection rate Type
(parts) (dots/mm) (.mu.m) (.mu.m) (pl) (A)
__________________________________________________________________________
Example 11 Acetylene glycol-EO adduct 1.5 14.2 114.4 44 44.6 2.6 12
Acetylene glycol-EO adduct 5 14.2 123.2 44 44.6 2.8 13 Acetylene
glycol-EO adduct 15 14.2 136.4 44 44.6 3.1 14 Acetylene glycol-EO
adduct 15 15.7 91.8 27 10 3.4 15 Acetylene glycol-EO adduct 10 14.2
116.5 38.5 30 2.9 16 Acetylene glycol-EO adduct 5 11.8 131.0 48.5
60 2.7 17 EO-PO copolymer 7 15.7 97.2 36 24.4 2.7 18 Nonylphenyl
ether-EO adduct 5 11.8 130.5 45 47.7 2.9 Comparative Example 7
Acetylene glycol-EO adduct 0.5 14.2 101.2 44 44.6 2.3 8 Acetylene
glycol-EO adduct 5 11.8 143.1 53 78.0 2.7 9 Acetylene glycol-EO
adduct 2.5 14.2 162.8 44 44.6 3.7 10 Sodium dodecylbenzenesulfonate
5 15.7 98.1 44 44.6 2.2
__________________________________________________________________________
TABLE 4 ______________________________________ Optical Density
Bleeding Feathering density irregularity
______________________________________ Example 11 .DELTA.
.smallcircle. .smallcircle. .smallcircle. 12 .smallcircle.
.smallcircle. .smallcircle. .smallcircle. 13 .smallcircle. .DELTA.
.smallcircle. .smallcircle. 14 .smallcircle. .smallcircle. .DELTA.
.smallcircle. 15 .smallcircle. .smallcircle. .smallcircle.
.smallcircle. 16 .smallcircle. .DELTA. .smallcircle. .smallcircle.
17 .smallcircle. .smallcircle. .smallcircle. .smallcircle. 18
.smallcircle. .smallcircle. .smallcircle. .smallcircle. Comparative
Example 7 x x .DELTA. .DELTA. 8 .smallcircle. x x .smallcircle. 9
.smallcircle. x x .smallcircle. 10 x x x x
______________________________________
As described above, the present invention gives color images of
high quality formed by dots of a precisely circle shape with
excellent color density without causing feathering, bleeding, and
color nonuniformity even on plain paper.
Furthermore, the present invention enables excellent recording
without failure of ejection after intermission of printing with
stability and without nozzle clogging.
* * * * *